A mysterious rebound in the emissions of ozone-depleting chemicals – despite a global ban stretching back almost a decade – has been traced to eastern China.

Research published by an international team today in Nature used a global network of monitoring stations to pinpoint the source of the rogue emissions. According to these data, 40-60% of the increase in emissions seen since 2013 is due to possibly illegal industrial activity in the Chinese provinces of Shandong and Hebei.

Chlorofluorocarbon-11 (CFC-11) is a powerful ozone-depleting chemical that plays a major role in the appearance, each spring, of the ozone “hole” over Antarctica.

In the past, CFC-11 had been used primarily as a propellant in aerosol products and as a foam plastic blowing agent. The production and consumption (use) of CFC-11 are controlled by the global Montreal Protocol. CFC-11 consumption has been banned in developed countries since 1996, and worldwide since 2010.

This has resulted in a significant decline of CFC-11 in the atmosphere. Long-term CFC-11 measurements at Cape Grim, Tasmania, show the amount in the atmosphere peaked in 1994, and fell 14% by 2018.

However, this decline has not been as rapid as expected under the global zero production and consumption mandated by the Montreal Protocol since 2010.

Background levels of CFC-11 measured at Australia’s Cape Grim Baseline Air Pollution Station, located at the north-west tip of Tasmania.CSIRO/Bureau of Meteorology

A 2014 study was the first to deduce that global emissions of CFC-11 stopped declining in 2002. In 2015, CSIRO scientists advised the Australian government, based on measurements compiled by the Advanced Global Atmospheric Gases Experiment (AGAGE), which includes those from Cape Grim, that emissions had risen significantly since 2011. The cause of this rebound in CFC-11 emissions was a mystery.

Global CFC-11 emissions based on atmospheric measurements compared with the expected decline of this compound in the atmosphere if compliance with the Montreal Protocol was adhered to.CSIRO/AGAGE

Montzka’s team concluded that if these increased CFC-11 emissions continued, the closure of the Antarctic ozone hole could be delayed, possibly for decades. This was a remarkable piece of detective work, considering that Mauna Loa is more than 8,000km from East Asia.

Suspicions confirmed

A still more detailed explanation is published today in the journal Nature by an international research team led by Matt Rigby of the University of Bristol, UK, and Sunyoung Park of Kyungpook National University, South Korea, together with colleagues from Japan, the United States, Australia and Switzerland. The new study uses data collected every two hours by the AGAGE global monitoring network, including data from Gosan, South Korea, and from an AGAGE-affiliated station at Hateruma, Japan. Crucially, Gosan and Hateruma are just 1,000km and 2,000km, respectively, from the suspected epicentre of CFC-11 emissions in East Asia.

The Korean and Japanese data show that these new emissions of CFC-11 do indeed come from eastern China – in particular the provinces of Shandong and Hebei – and that they have increased by around 7,000 tonnes per year since 2013.

Meanwhile, the rest of the AGAGE network has detected no evidence of increasing CFC-11 emissions elsewhere around the world, including in North America, Europe, Japan, Korea or Australia.

Yet while this new study has accounted for roughly half of the recent global emissions rise, it is possible that smaller increases have also taken place in other countries, or even in other parts of China, not covered by the AGAGE network. There are large swathes of the globe for which we have very little detailed information on CFC emissions.

Map showing the region where the increased CFC-11 emissions came from, based on atmospheric measurements and modelling.University of Bristol/CSIRO

Nevertheless, this study represents an important milestone in atmospheric scientists’ ability to tell which regions are emitting ozone-depleting substances and in what quantities. It is now vital we find out which industries are responsible for these new emissions.

If the emissions are due to the manufacture and use of products such as foams, it is possible that, so far, we have seen in the atmosphere only a fraction of the total amount of CFC-11 that was produced illegally. The remainder could be locked up in buildings and chillers, and will ultimately be released to the atmosphere over the coming decades.

This study highlights the importance of undertaking long-term measurements of trace gases like CFC-11 to verify that international treaties and protocols are working. It also identifies shortcomings in the global networks for detecting regional emissions of ozone depleting substances. This should encourage expansion of these vital measurement networks which would lead to a capability of more rapid identification of future emission transgressions.

Australia’s report card on reducing its greenhouse gas emissions is not exactly glowing, but there are ample opportunities to get it on track during this period of rapid change in the energy sector. Greater use of renewable electricity sources like wind and solar are playing a large part in reducing emissions, and gas can also lift its game.

Gas provides nearly one quarter of Australia’s total energy supply. Around 130,000 commercial businesses rely on gas, and it delivers 44% of Australia’s household energy to more than 6.5 million homes which use natural gas for hot water, domestic heating, or cooking.

Gas has lower greenhouse emissions than most other fuels, and the gas used in power generation has about half the emissions of the current electricity grid.

Even so, natural gas can do more to help Australia meet its carbon-reduction targets.

An industry document released last year, Gas Vision 2050, explains how new technologies such as biomethane and hydrogen can make that happen, by replacing conventional natural gas with low-emission alternative fuels.

Around the world

Worldwide, renewable natural gas is dominated by biomethane, which can be generated from organic materials and residues from agriculture, food production and waste processing.

Multiple products of anaerobic digestion.Modified from ADBA with permission

Of course, biomethane is just one way in which Australia can make the transition to a low-emissions future. But as natural gas is already touted as a “transition fuel” to a low-carbon economy, these new technologies can help ensure that existing gas infrastructure can still be used in the future.

Vivid scenes of worried Cape Town residents clutching empty water vessels in long snaking queues are ricocheting around the globe. Everyone is asking, “How did this happen?” Or, more precisely, “Can it happen in my city?” The importance of effective water management has been shoved, blinking, into the limelight.

In Australia we’re watching somewhat nervously, grateful to have been spared the same fate – for now, at least. Experts tell us that the key is “water divestment” – that is, don’t put all your eggs in one basket (or, perhaps more appropriately, don’t get all your water from the same tap).

Groundwater, the great salvation of parched cities and agricultural development, is the world’s largest freshwater resource. The volume of fresh water in all the world’s lakes, rivers and swamps adds up to less than 1% of that of fresh groundwater – like putting a perfume bottle next to a ten-litre bucket.

What’s more, because it’s underground, it is buffered somewhat from a fickle climate and often used to maintain or supplement supply during times of drought.

Yet caution is required when developing groundwater. Sinking wells everywhere, Beverley Hillbillies style, is unwise. Instead, robust groundwater management is required – defining clearly what we want to achieve and what are we prepared to lose to get it.

Despite the common perception of its abundance, groundwater is not inexhaustible. Its management is fraught with minefields greater and more enigmatic than those of surface waters. It is, after all, much easier to spot when a reservoir is about to run dry than a subterranean aquifer.

Subsidence can be surprisingly rapid, as in the case of this example in California’s San Joaquin Valley.USGS

Only when aquifer depletion is already quite advanced do we begin to see the tell-tale signs at the surface: metres and metres of subsidence, huge cracks in roads, and dried-up wetlands clogged with dead trees and dried-out bird carcasses.

For the most part, however, groundwater remains out of sight, hidden beneath many metres of soil and rock. We only remember it is there when something goes wrong, such as a drought, at which point people begin raving about groundwater, location, yield, salinity, stygofauna – wait, what?

Actually hardly anyone cares about stygofauna; most people have never heard of these tiny subterranean creatures, and you will certainly never see one as a state emblem. Mound springs? What are they? Clearly being underground has left groundwater with an image problem.

There was much media coverage of water theft from the Murray River, with broadcast journalists reporting breathlessly from tinnies, and dramatic footage of huge pumps sucking swirling brown water from a sluggish river. Film of groundwater pumps sedately slurping water is much harder to get, because bores tend to be on private property, often hidden inside little tin shacks and kind of boring, really.

Groundwater just doesn’t capture the public imagination. Great reservoirs and rivers are evocative of wilderness and adventure; they almost make you want to build a little raft and float lazily away, Huck Finn style. But the thing is, groundwater feeds many great rivers, supplying base-flow, so when we suck water out of wells, in many instances we may as well be sucking out of rivers.

Despite this connectivity, in many regions groundwater and surface water are managed separately. This is akin to treating to your left hand as a separate entity to your right. Regulation of groundwater lags behind that of surface water and, in many parts of the world including the United States, China, India and Australia, groundwater is overexploited and pumped prolifically, leading to severe social and environmental impacts.

Mound springs support unique and endemic ecosystems and bubbling clear cold water, a welcome sight for dusty travellers. And as for the aforementioned stygofauna, well, what could be cooler than a blind cave eel?

It is crucial that we ensure our groundwater management is effective and robust in the face of drought. It is no longer enough just to write management plans; we must put them to the test by running our groundwater models through a range of future climate and management frequency scenarios. We need increased investment in groundwater management planning, and for management to be conducted in conjunction with surface water management.

With many cities’ water supplies drying up before our eyes, we also need to remember to think about the water we cannot see.

An international team of astronomers has discovered that the supermassive black hole at the centre of our galaxy might be the source of mysterious high-energy cosmic rays that bombard the Earth on a daily basis.

The discovery, reported in Nature, brings new answers to one of astronomy’s most longstanding mysteries.

Back to the source

In 1912 Victor Hess found that the Earth was being bombarded by subatomic particles travelling at tremendous speeds that originated from outer space. He called the particles “cosmic rays”. But the origin of these high energy particles has remained a mystery for more than 100 years.

“How cosmic rays are created and accelerated at very high energies is the big question astronomers are trying to understand,” said Associate Professor Gavin Rowell, an astrophysicist from the University of Adelaide, who was involved in the Nature study.

One theory was that cosmic rays are produced during supernova explosions. These create “remnants” that send shock waves throughout the galaxy. This electrically charges particles in space, which are then accelerated to near the speed of light, eventually hitting the Earth.

However, because the particles are mangetically charged, any magnetic field in space will change their direction. That means it’s difficult to determine their origin once they strike our atmosphere.

In this study, the researchers used the High Energy Spectroscopic System (HESS) telescopes in Namibia to look for the very fast flashes of light created when cosmic rays collide with the Earth’s atmosphere.

Using this data, the researchers were able to estimate the direction of the cosmic ray, and found it pointed back towards the centre of our galaxy.

This coincides with the location of what is believed to be a supermassive black hole, with a mass of 4 to 5 million solar masses. The HESS team suggest that the huge gravitational force exerted by the tremendous mass of the black hole was able to accelerate the particles to their incredibly high velocities.

“This result adds a new dimension in cosmic rays, and how the cosmic rays our galaxy is producing could also come from this massive central black hole,” Rowell said.

Cosmic Cluedo

Professor Geraint Lewis, an astrophysicist at the University of Sydney, emphasised that the study also makes us aware that the universe can do things that far outstrip what we are capable of here on Earth. However, our understanding of cosmic rays is still far from complete.

He mentioned that the biggest question is explaining the precise cause of the particle acceleration.

“It is like a game of Cluedo: they’ve tied down what they think is the site of the murder, but now they are trying to locate the weapon,” he told The Conversation.

What it does tells us is that the cosmos can accelerate particles to velocities that far exceeds what we are capable doing on Earth.

“These particle accelerators in outer space put the Hadron Collider in the shade,” he said.

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Despite the nuclear problems in Japan following the recent earthquake and tsunami disaster there, consideration still needs to be given to nuclear power as a possible green energy source – certainly I believe that this technology warrants more investigation. The article below raises the possibility of mini-nuclear reactors as being a possible and safer answer to our energy needs.